Which measurement of length is the smallest?
a- 9x10–6 m
b- 7x10–5 m
c- 7 x101 m
d- 9x102 m

The first thing we will do for this case is to define the scientific notation:

It is a way of writing numbers that accommodate values too large or too small to be written in a conventional manner.

A number written in scientific notation follows the following pattern:

Where,

The number m is called "mantissa" and e the "order of magnitude"

The smallest length then, is one that has the smallest order of magnitude:

The measurement of length that is the smallest is:

option A